MALIGNANT GASTROINTESTINAL STROMAL TUMOR
Gastrointestinal Stromal Neoplasm; Gastrointestinal Stromal Sarcoma
Malignant Gastrointestinal Stromal Tumor (GIST) is a rare type of soft tissue tumor that usually begins in cells in the wall of the stomach, intestines, or rectum. GIST tumors are caused by mutations in the PDGFRA gene. Clinical features of the GIST depend on the size and site of the tumor and may include acute or chronic bleeding, intestinal obstruction, perforation, alteration of bowel habits, difficult to distinguish abdominal discomfort, dysphagia (difficulty swallowing) and externally palpable abdominal mass. The most common symptoms associated with GISTs are vague, nonspecific abdominal pain or discomfort. GISTs may also produce symptoms secondary to obstruction or hemorrhage (GI bleeding, malaise, fatigue, and dyspnea). The obstructive symptoms can be site-specific (e.g., dysphagia with an esophageal GIST, constipation with a colorectal GIST, obstructive jaundice with a duodenal tumor, etc.)
DIAGNOSTIC TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING
Diagnostic testing: Imaging tests such as X-ray, MRI, CT or PET scans; Barium x-rays; Barium swallow tests (upper GI series); Enteroclysis; Barium enema (lower GI series); Capsule endoscopy; Double Balloon Enteroscopy; Endoscopic Ultrasound; Surgical biopsy; Fine Needle Biopsy or Blood tests.
Physical findings: The most common presentation of GIST is GI bleeding, GI obstruction, appendicitis-like pain, constipation, fatigue, difficulty swallowing, anemia due to GI bleed, and feeling of stomach fullness (satiety).
ONSET AND PROGRESSION
GIST tumors range from slow growing indolent tumors to aggressive malignant cancers with the propensity to invade adjacent organs, metastasize to the liver, and recur locally within the abdomen. Most GIST tumors are diagnosed at an advanced stage and have a poor prognosis. These tumors are most commonly diagnosed between ages 55 – 65 years of age, and rarely are discovered in younger adults.
Surgery with complete resection of GIST is the preferred method of treatment for localized tumors. However, surgery has limited efficacy in the treatment of recurrent and metastatic gastrointestinal stromal tumors, as compared with sarcomas in the extremities. The development of drug therapy (i.e. imatinib) targeted at specific characteristics of cancer cells in GIST has improved the treatment of this tumor compared with surgical removal alone.
SUGGESTED PROGRAMMATIC ASSESSMENT*
Suggested MER for evaluation:
Clinical history and examination that describes the diagnostic features of the impairment.
Pathology report documenting type and stage of tumor.
MRI or CT scans.
Abdominal endoscopy, enteroscopy, or ultrasound.
Suggested Listings for Evaluation:
Since many of these tumors are benign, listing level cancerous tumors must be documented as inoperable, unresectable, extending to surrounding structures (for example, the omentum), recurrent, or with metastases.
When occurring in the stomach, which is the organ where most GISTs originate, any metastases to or beyond the regional lymph nodes will meet/equal 13.16B2.